In the fabrication of integrated circuit devices, such as an array of semiconductor static random access memory (SRAM) cells, one of the crucial technological issues is the fabrication of parallel electrically conducting metallization lines having a spatial periodicity that is as small as possible, in order to conserve semiconductor chip space. In prior art, this periodicity is ordinarily limited by the smallest feature obtainable by means of standard photolithography techniques, of masking and etching to fore all be desired metallization lines simultaneously. However, because of the non-vanishing wavelength of the light used for such photolithography, the spacing S between adjacent lines is, in present technology, at least approximately 0.4 .mu.m unless advanced techniques like phase-shifting or direct-writing lithography be used, which can be undesirable.
When using aluminum for the metallization lines, in present technology the width of each line should be no less than approximately 0.7 .mu.m to 0.9 .mu.m, preferably approximately 1.0 .mu.m, lest electromigration effects due to high electrical current density flowing in the lines during operation of the device cause voids (gaps) to form in the lines and hence cause undesirable open circuits in the device, and lest stress in the aluminum also cause undesirable voids therein. Thus, the spatial periodicity of the lines preferably is approximately equal to at least (1.0+0.4) .mu.m=1.4 .mu.m. In the case of an SRAM cell, for example, having an aluminum bit line B and a parallel, complementary aluminum bit line B, the width of each SRAM cell preferably is thus approximately equal to at least 2.times.1.4 .mu.m=2.8 .mu.m, although smaller widths can be made at some sacrifice of reliability due to electromigration and open circuits. It would therefore be desirable to have a method of reducing the spatial periodicity of metallization lines, and hence of conseling chip space, and thus, for example, of enabling an increase the number of SRAM cells per unit area of the chip.